1. Field
Embodiments of the present inventive concepts relate to semiconductor devices and methods of fabricating the same.
2. Description of the Related Art
In the manufacture of highly integrated semiconductor devices, methods of increasing the mobility of carriers within channel regions are under active research in an effort to enhance device performance. In one approach, it has been determined that enhanced carrier mobility is achievable by applying a tensile or compressive stress to a channel region by forming a stress layer in a semiconductor device.
Specifically, electron mobility can be enhanced in an n-channel metal oxide semiconductor (NMOS) region in which major carriers are electrons by forming a tensile stress layer. Also, hole mobility can be enhanced in a p-channel metal oxide semiconductor (PMOS) region in which major carriers are holes by forming a compressive stress layer. To further enhance the effect of applied stress, each of a source region and a drain region may be formed as a tensile stress layer or a compressive stress layer by, for example, a selective epitaxial growth (SEG) process.
In the source and drain regions formed by the SEG process, non-uniform crystal growth can lead to defects such as a stacking fault defects. Such defects can negatively affect the reliability of the resulting semiconductor device.